In many orthopaedic surgical procedures, there is need to drill holes in the bone of the patient, in order to insert fixation devices or surgical inserts. Surgical screws are widely used in orthopedic surgery to fix broken bones as well as to maintain the broken bones in alignment during the healing process. The hole for receiving these inserts or fixation devices are generally prepared by drilling through a cannulated drill guide, and many such drill guides have been described in the prior art.
In U.S. Pat. No. 5,403,322 to J. E. Herzenberg et al, for “Drill guide and method for avoiding intramedullary nails in the placement of bone pins”, there is described a drill sleeve or a guide-wire sleeve having a toothed or serrated distal end, such that the sleeve bites into the bone into which the drilling is being performed, and constitutes a firm guide for the drill. In this patent, there is a description of how the surgeon inserts the guide wire sleeve through the drill sleeve until the serrated distal end touches the bone. He then strikes the guide wire sleeve proximal end, causing the teeth or serrations to be imbedded (i.e., bite) into the bone. In this invention, the sleeve is not used on its own, but is the fourth rigid fixation point of a four-bar construction, thus rendering the drilling position highly stable. As stated in this patent, “(t)his resulting construct thus attains the stability required to prevent the guide wire, drill bit, or bone pin from walking or skiving off the side of the slippery, rounded contour of bone, known to be a problem without the stability attained with the four-bar construct as above-described.”
In U.S. Pat. No. 6,607,530 to A. Carl et al., there is described in FIG. 3A a drill guide sleeve having at its distal end a plurality of fixed teeth that bite into the bony surface of a vertebra to assist in preventing slipping of the drill guide.
In U.S. Pat. No. 7,060,068 to S. G. Tromanhauser et al., for “Vertebrae fastener placement guide”, there is described another composite guide system construction having two guiding members each of which has a bone-engaging surface with serrations to minimize slippage of the guide against the bone.
However, in many cases, such a rigid structure is not used, and the drilling guide is instead used solo, often hand held, such as in U.S. Pat. No. 6,416,518 to E. N. DeMayo for “Combined surgical drill and surgical screw guide”. In such use, the above mentioned problem of skiving off the bone can be significant. When used on a reasonably flat bone surface, and at normal or close to normal incidence to the bone, many or even all of the teeth or serrations on the end of the sleeve grip the bone surface together, thus providing non-slipping functionality to the drill guide. However, when the hole has to be drilled into a small diameter bone having a distinctly curved outer surface, or even when the hole is to be drilled in a flat bone surface, but at a significant angle of incidence to the bone surface, it is likely that only a small number of the teeth or serrations at the end of the guide sleeve will contact the bone, and there is then danger that the guide sleeve will slip during use, rendering the hole position inaccurate.
There therefore exists a need for a surgical drilling guide which can be used independently of a larger drilling and guiding construction, and which nevertheless provides a rigid drilling positioning, thus overcoming at least some of the disadvantages of prior art guides.
The disclosures of each of the publications mentioned in this section and in other sections of the specification, are hereby incorporated by reference, each in its entirety.